For the production of miso, soy, natto, boiled beans, soy-cooked beans, etc. through processing of pulses such as soybeans and azuki beans, it is common practice to soak raw pulses in water for a certain time period to let them absorb water, boil the soaked pulses in water or steam them in a pressure cooker or the like, and subject them to further processings. In such a production process, it is important to strike a balance between tenderness and firmness of boiled or steamed pulses, and the nutritional value of the end product depends largely on whether said balance can be achieved by judicious process control.
Heretofore, for the purpose of tenderizing pulses to a uniform firmness, addition of phytic acid or a phosphate salt (e.g. sodium pyrophosphate) to soaking water has been practiced. However, the use of phytic acid or a phosphate salt results in various problems, for example in the case of the phosphate salt, the absorption of minerals is inhibited, leading to major changes in the post-processing nutritional value of pulses with the inherent nutrients being more or less deprived of. In addition, an adverse influence on the environment is also apprehended in the disposal of waste water.
Having been made in view of the above situation, the present invention has for its object to provide a novel bean tenderizer which enables the production of quality processed pulses with an assured balance between tenderness and firmness with ease, is capable of drawing out the inherent nutrients of pulses unaffected, and is eco-friendly, and a technology by which processed pulses can be produced with good efficiency.